duncan



(No Model.) 6 Sheets-8heet 1.--

G. S. DUNCAN. HYDRAULIC MACHINERY.

No. 478,225. Patented Ju1y.5, 1892.

Fg; J.

INVENTOI? ATTOHNE VS (No Model.) 6 Sheets-Sheet '2.

G.S.DUNCAN. HYDRAULIC MAGHINERY.

No. 478,225. Patented July '5; 1892.

INVENTUR WITNESSES. ,L

QNo Model.) 6 Sheets-Sheet 3.

' G. S. DUNCAN.

' HYDRAULIC MACHINERY.

No. 478,225. PatentedJuly 5, 1892.,

W/TNESSES: INVENTOI? ATTORNEYS THE "cams PETERS co.. Fume-Luna,wnsnmm'nu, o. c

(No Model.)

6 Sheets--Sheet 4.

G. S. DUNCAN. HYDRAULIC MACHINERY.

WITNESSES mam PITEH Fag. 4.

Patented July 5, 1892.

INVENTOH $2M By Q A TTORNE Y8 s 120., rum vunim, WASKINGYON, D. c.

(Na Model.) 7 6 Sheets-Sheet 5. G. S. DUNCAN.

HYDRAULIG- MACHINERY.

Patented July 5, 1892.

WITNESSES: INVENTOH m 8 9mm rron/v5 rs "me Moms vn' ns cm, mow-mug,vusmnawu, u, c,

(No Model.\ 6 Sheets-Sheet 6'.

G. S. DUNCAN.

HYDRAULIC MACHINERY.

Patented July 6, 1892..

12 .10. rnq zz.

:i' it 1 :1 ll 6 h i :l I I 3 4 l a a .E

' INVENTOH W/TNESSES: v

ATTORNEYS UNITED STATES ATENT OFFICE.

GEORGE SMITH DUN CAN, OF MELBOURNE, VICTORIA.

HYDRAU LIC MACjHlN ERY.

I SPECIFICATION forming part of Letters Patent No. 478,225, dated July5, 1892.

Application filed February 4, 1891- Serial No. 380,154- (No model.)

of hydraulic machinery, and is more espe cially applicable to lifts andpresses which are operated by water under a high pressure;

Its object is to reduce the quantity of powerwater required foroperating hydraulic machinery, and it accomplishes this object partly byautomatically regulating the amount of power-water used, according tothe load to be raised or work to be done, and partly by automati'callyreturning a certain proportion of water into either the pressure-main orinto an accumulator, according to the weight of the descending load.

It consists in the combination, with the main operating-cylinder of ahydraulic machine, of two or more cylinders of varying area (which Ishall hereinafter refer to as governing-cylinders) connected one withsaid main operating-cylinder and the other or others with a multiplevalve or valves connected with apparatus such as is hereinafterdescribed, whereby they are automatically opened or closed according tothe pressure in said main operating-cylinder, so as to admit thepowerwater into one or other of said governing-cylinders according tothe pressure in said operating-cylinder-that is, according to the weighton the ram or the work to be done.

It likewise consists in the combination, with the two or moredifferent-sized governing-cylinders, which, as above mentioned,areaccording to this invention connected to the main operating-cylinder ofthe hydraulic machine, of a multiple valve or valves connected with anapparatus, such as hereinafter described,-

whereby said valve or valves are automatically operated by the pressurein said main operating-cylinder, so as to open com munication betweensaid governing-cylinders and either the hydraulic main or an accumulatorwith comparatively low-pressure lifts.

or accumulators, in order that a certain pro-' portion of water may bereturned from one ing-cylinderthat is, according to the weightof thedescending load.

Having now briefly described and ascertained the main features of myinvention, I will proceed to describe the same more particularly,reference being had to the accompanyin g drawings, 'wherein Figure 1 isa sideelevation of a complete set of my improved means for automaticallyregulating the amount of power-water used in hydraulic machinery,according to the weight to be raised or work done, and for automaticallyreturning a certain proportion of Water either to the main or else intoan accumulator, according to the weight of the descendingload. Fig. 2 isa vertical transverse section on line 2 2, Fig. 1. Fig. 3 is a similarview to Fig. 2, but illustrating a simpler form of my invention, such asI prefer to employin connection Fig. 4 illustrates a modification of myinvention which is adapted for use where the lift is op-- erated bywater stored in tanks at various altitudes. construction of themechanism which I employ for operating the different valves in order toallow the pressure-Water to flow into the various-sized cylinders,according to the power required. Fig. 6 is a vertical section Fig. 5 isaplan illustrating the of said mechanism on line 6 6, Fig. 5, while Fig.7 is a front elevation thereof; and Fig.8-

is a vertical section on line 8 8, Fig. 5. Fig. 9 is a detached sideelevation of one of the parts of said mechanism. Fig. 9 is asimilar viewof another form of the same part, showing its construction when requiredto open the valve connected with it more than once in the one operation.Fig. 10 is a similar view of the same detail, but illustrating amodification thereof; and Fig. 11 is an end elevation thereof. Fig. 12is a side elevation of yet another detail, and Fig. 13 is a diagrammaticview of an apparatus which has been devised for the purpose ofcompensating for any reduction in the pressure of the powerwater. Fig.14: is a detached view of part of my invention, illustrating theapplication thereto of a contrivance for automatically opening one ormore of the governing-valves in the event of the weight of the cagebeing rendered inoperative by reason of its being supported upon thefloorof the lift-well, while Fig. is a diagrammatic view of anotherapplication of my invention, illustrating it as operated by the pull ofthe haulage-rope.

Similar letters of reference indicate the same or corresponding parts inall the fig- A represents the main ram-cylinder of the lift, and A theram working therein, while B represents a cylinder connected with saidram-cylinder A and of suflicient capacity to contain enough oil or waterto entirely fill the said ram-cylinder. Inside this cylinder B works apiston 1), formed with an upwardlyprojecting plunger 1), fitted at itsupper end with a smaller piston 0, working inside a second cylinder C.This said smaller piston c is likewise provided with anupwardly-projecting plunger cl, which projects up into the smallestcylinder D of the series. Stuffingboxes I) c d are provided for theplungers b c d to work through. The upper ends of the cylinders B C Dare each connected by a separate pipe 6* f* 9* with a stop-valve E F G,as clearly illustrated.

The different areas of the pistons 12 c and ram cl may be varied to anydesired extent. For instance, with a pressure of, say, seven hundredpounds to the squat-cinch of powerwater I may so construct them as thatthey automatically give a choice of, say, either two hundred and fiftypounds, three hundred and fifty pounds, four hundred and fifty pounds,five hundred and fifty pounds, six hundred and fifty pounds, or eighthundred pounds pressure to the square inch on the lift-ram, it beingobvious that, if desired, one or more of said valves El G can be openedat the same time, so as to put a corresponding number of said cylindersin communication with the power-water supply.

'The spindles efg of the valves E F G extend upwardly throughstuffing-boxes in the casings of said valves and are formed each with acollar e f 9' near the upper ends, and they may be weighted; or, ifpreferred, a weighted arm 6 f g Figs. 5, 6, and 7, may be arranged tobear upon their upper ends with any force required to keep the valvesnormally closed. Small pivoted trip-levers c 5 5 f g project underneathand engage each with one of the collars ef' g on the valve-spindles e f9, while with each of said pivoted trip-levers engages one of a seriesof pawls, cams, or catches e f g, which are mounted upon a rock-shaft h.The engaging surface of these cams, pawls, or catches e" f g are made ofa greater or less incline, respect ively--as, for instance, the engagingsurface of e may be made horizontal, that of f of a slight incline, andof g of a still greater incline. Thus it will be seen that upon therocking of shaft h the cam whose engaging surface is nearest thetrip-lever will accordingly open its attached valve first and the restwill operate in their turn. Upon this latter is a short crank-arm it,connected by a rod h with a piston or plunger 7L3, working in a smallcylinder II. This cylinder is in communication through a small pipe 72,with the interior of either the cylinder B or the cylinder A, it beingobviously immaterial which, because both of said cylinders are, as abovementioned, in open communicationone with the other, and therefore thepressure in the one is always the same as in the other. The pressure ofwater in the cylinder B or main operating-cylinder A tends to force theplunger or piston its up against the resistance of a spring 71 whosepressure can be regulated at will, in order to determine the pressurerequired for opening the valves E F G. I represents thepower-water-supply main or a pipe leading therefrom, and J theexhaustpipe leading into an overhead tank or other storage-reservoir K.This power-water main I and exhaust-pipe J are each fitted with a stopvalve i j, connected together by some suitable contrivance which willinsure their.

working alternately, so that when one is opened the other will be shut.Said valves may be operated bya rod, chain, or rope pass ing through thecage of the lift, and therefore under the control of the attcndaut,inthe ordinary manner.

In order thata certain amount of water proportionate to the load maybeeither returned to the power-water main or else be forced into anaccumulator, the cylinders B O D are connected with the valves L M N,whose spindles are operated by an apparatus which is similar to that towhich the spindles of the valves E F G are connected. By this means saidvalves may be automatically closed, according to the pressure of watercontained in the operatingcylinder 0, whose functions and constructionare similar to that of the cylinder H, above described. This cylinder 0is in open communication with the lower partof the cylinder B by pipe 0,corresponding to the pipe M.

The operation of my invention is as follows: Assuming, for instance,that it is required to raise the cage of the lift with the attendant init, or with, perhaps, the attendent and only one light passenger, then Iemploy the small governing-cylinder D-that is, the strength of thespring h is so proportioned that the plunger or piston 72, will beraised sufficiently by the pressure of water in the cylinders A and B tocause it to turn the rock-shaft h enough to cause the pawl or cam g toopen the valve G through the medium of the small rocking lever g andcollar g, the effect he in g to open comm unication between thepressure-main I and the cylinder D as soon as the stop-valve i is openedby the lift-attendant in the ordinary manner. The power-water will thenbe free to flow from the poweronain I through the valve G along the pipeg into said Cylinder D, when it'will for'cedown the ram d and pistons cb, and will thereby force the water or oil outof the cylinder B into theram-cylinder A, and thus lift the cage.

the pressure in the cylinders A and B be in-' creased by more passengersor other extra weight getting into or being placed in the lift the valveF, leading into the governing-cyL' inder C, will be opened, the valve Gbeing then closed, and the'pressure of water thus being caused to actupon the piston 0, whose area, being greater than that of the ram d,will enable the increased load to be raised. It will be obvious that thecams or catches e f g maybe combined and arranged in many differentways. For instance, I may, through their instrumentality, first opencommunication to the small governing-cylinder D, then with the nextlargest governing-cylinder C, then with the upper part of the nextlargest B, after which I may cut off communication with the upper partof said governing-cylin der B and open communication to both of thegoverning-cylinders O and D at the same time, (a cam or pawl 9*, such asis illustrated in Fig. 9, being employed to reopen the valve G,). afterwhich I might substitute the upper part of B for O, and finallyI mightso arrange said pawls or cams as that all three cylinders B, O, and Dwould be in operation together, in which case, if their collective areaswere sufficiently large, I might intensify the water in the cylinders Aand B to a greater pressure than that of the power-water. is coming downwith a fairly heavy load, the medium-sized piston 0 may be arranged toforce water back into'the pressure-main. In order to effect this, thepressure of water in the cylinder B has torai-se the piston or plungerin'the cylinder .0 to compress the spring 0 and turn the rock-shaft 0round sufficiently far to close thevalve M through the medium of the camor catch m, which is mounted upon said shaft, and is, -'constructed in asimilar manner to the cams 1 g above described. The effect of this willbe that the water contained in the cylinder 0 will be forced to passthrough the retention or back-pressure valve f into the power-main Lthatbeing obviously the only course open to it. The water from" thegoverning-cylinders B and D will be free to pass through the valves L Nand up the discharge-pipe J into the tank or reservoir K. In asimilarmanner, should a lighter load be coming down in the lift, the valve Lwill be closed, andthe water in the governing-i cylinder D will beforced along the pipe 9* and through the retention or back-pressurevalve g into the main; or, if a larger load be When the lift descendingin the cage, the valve N will be closed and the water in the upper partof the cylinder B will be forced to pass through the pipe e* andback-pressure valve 6. into said main I; or, under some circumstances,any two or even all of the governing-cylinders B O D might be coupledtogether and be caused to force water back into the main cams, such asare illustrated in Fig. 9, being employed to open two of the valves asecond time. It will be obvious that the amount of this returned waterwill be regulated by-the areas of the pistons 19 and c and ram cl andthat the question of which one of the three is operating will bedetermined by the pressure in the cylinder B acting upon the piston orplunger in the cylinder 0, as above described.

In order to allow two of the cylinders B C D to discharge into themainwhile the third cylinder discharges into the waste-watertank K, smallback-pressure or retention valves e f g are inserted in the pipes e* f*9* close to the stop-valves E F G,thus preventingthe Water from beingsimply forced out of one of the cylinders B O D into another one, andthence into the waste-water tank K, instead of passing into the main 1.

In order to allow either of the two valves F G to be opened-andafterward returned to their normal positions,while at the same timeallowing the valve E to be opened, I either construct the twopawls orcams f g as illustrated in Figs. 10 and 11, or else I secure an arm Pupon the rock-shaft 72, and adapt said arm to engage with a pair ofpawls or catches p 1), (Figs. 8 and 12) on a vertically-sliding frame padapted to raise the ends of the pivoted trip-levers f 9 so as'to allowthe cams or catches f g to pass them and so return to their normalpositions. The pawls p are provided with weighted tail-pieces, wherebythey are normally kept projecting into the center of said frame, asclearly illustrated in full lines in Figs. 8 and 12. The bent arm orlever P and the pawls p are so arranged that just when the valve F isfully opened said arm will engage with said pawls p p, sothat in theevent of the passengers getting off the lift'said arm will raise thesliding frame 10' IIO and will carry with it the ends of either one or tboth of the trip-levers f 9 thus depressing the other ends of saidtrip-levers, and thereby allowing the pawls or cams f g to pass them andreturn to their normal positions, said pawls or cams being each securedupon the shaft h by a pin 19 (tide Fig. 9,) working in a slot 19 cutinsaid pawl, and so arranged as to allow the shaft h a certain amount ofrotation before it carries said pawl or cam with it, thereby allowingthe ends of the trip-levers f g to be lowered sufficiently far to allow1 said pawls or catches f g to pass them and return to their normalpositions. It preferred,

the pawls or catches f g might be providedwith a small pivotednose-pieceP, (see Figs.

instead of this contrivance the end of each of 10'and*11,-)normally'pressed outward by small spring p in such a manner as that itwill engage with the trip-levers f g on its downward movement, but willbe free to pass them on its upward movement. A similar arrangement toone or other of those just described is provided on the opposite side ofthe machine for use in. connection with the operating-gear of the valvesL M N. If preferred, suitably-shaped cams might be mounted upon theshaft 0 and be arranged to effect the desired object of closing thevalves L M N by allowing them to be operated upon by springs m** of,whose tendency is to always keep them closed, or said cams might beconstructed to give somewhat when closing said valves, as will be wellunderstood by all persons skilled in the art to which this inventionrelates.

To provide against the result of the reduction of the pressure-waterbelow its standard or normal value, I have devised the apparatusillustrated in Fig. 13, in order that an auxiliary governing-cylindermay be brought into operation to, as it were, assist the others, and soprovide sufficient power to lift the load with such reducedpressure-Water. This apparatus consists of a cylinder Q in opencommunication with the pressure-main I and fitted with a piston q,having a downwardlyprojecting spindle q, connected at its lower end withthe arm 'r of a small stop-valve R, inserted in a pipe r, connecting thecylinder Q with the lower end of the cylinder 13, and therefore with themain operating cylinder of the lift or other hydraulic machine. Aroundthe spindleq is arranged a coiled spring S, whose tendency is to alwaysraise said spindle and the piston q against the pressure of water fromthe main 1. This said spring is so adjusted as to be able to force thepiston q upward in the event of the pressure in the main I falling belowits normal value, the efiect being to open the valve R and so admit thewater from the lower part of the cylinder B to the under side of thepiston g, which will then be forced upwardly against the pressure of asecond adjustable spring (1 according to the varying pressure in thelower part of the cylinder Bthat is, according to the weight of the loadto be raised or other work done. This movement of the piston q isutilized for the purpose of turning on one or other of tl e valves E FG, in addition to the one or ones already opened by the instrumentalityof the cylinder H, rock-shaft h, and cams or pawls 2 g a secondrock-shaft if being mounted below the first one h and be ing providedwith cams or pawlst t i adapted to raise one or other of the spindles ef g of the valves E F G, it being understood that said camsor pawls t tt are so adjusted as to only operate upon a valve not already opened. Bythis means, should the pressure in the main fall below its normal value,an extra governing-cylinder B, C, or D will be utilized to, as it were,assist those already in use, and thus the decrease of pressure will beable.

compensated for. The arrangement illustrated in Fig. 3 is similar in itsessential features to that described with reference to Figs. 1 and 2,but is simpler, owing to the fact that only two cylinders (B and C) areemployed. This modification is suitable for low-pressure lifts where itis only required to haveachoice of, say, three powers, it being obviousthat the pawls or cams e f might in the arrangement illustrated be soarranged as to turn the power-water into the small governing-cylinder Cin the event of only a light load being in the cage, or into thegoverning-cylinder B in the event of there being a heavier load, or intoboth in the event of its being required to employ the maximum poweravail- On the downstroke one or other of the governing-cylinders B (3would be automatically put in communication with the powermain by thevariation of pressure in the lower part of the cylinder B acting upon arockshaft 0. This arrangement being, as above stated, merelyasimplification of that already described with reference to Figs. 1 and 2will not need any further explanation.

Fig. 4 shows the application of my invention to a lift operated by watercontained in three cisterns supported at varying altitudes. Each of saidcisterns B C D is connected with one of three valves E F G,which are allconnect ed with the main lift-cylinder Aand are operated by mechanismsuch as is illustrated in Figs. 6 to 12, so that,as hereinbeforementioned, either of the valves. E, F,or Gwill be opened, according tothe power required to raise the load on the ram A, such opening beingeffected by the pressure of water in the lift-cylinder A acting upon thepiston or plunger 71 in the manner above described with reference to thecorrespondingvalves in Fig. 2. \Vater will be returned into one or otherof the cisterns D C, according to the pressure in the cylinder A, byopening one or other of the valves L or M by means of an apparatusconstructed as above described and arranged to be operated by thepressure in said cylinder. The operation of this modification of myinvention is as follows: Assuming that only a light load is to be raisedby the ram A, then the pressure of water caused by said lead in thecylinder A will turn on the valve E, so as to utilize the water in thelowest tank D. On the other band, should the lift be loaded to somewherenear its maximum carrying capacity, the valve G will open, and thus thehead of water in the highest tank B will be used. Upon the ram Adescending the water will (provided the load is heavy enough) he forcedfrom the cylinder Athrough one or other of the valves L M (according tothe pressure in said cylinder)'into one or other of the tanks C D, thusobviating the necessity for pumping that amount of water up into saidtanks by the expenditure of valuable power.

From the foregoing description it will be obvious that with the aid ofmy invention I am enabled to effect a considerable savingin the amountof power-water required for worklng hydraulic lifts or other hydraulicma- "chine'ry, because, instead of, as 'heretofore,

filling the ram-cylinder with high-pressure 'water at each stroke,irrespectivelyof whether a heavy or alight load is to be raised, Imerely use sufficient water to accomplish the desired object. Moreover,on the return-stroke or descent I utilize the weight of the descendingload to force a certain proportional quantity of water either back intothe water-main or else into an accumulator.

Referring to Fig.14, U represents an arm which is keyed or otherwisefixed upon the rock-shaft h and whose outer end engages with a lug orstop it upon the spindle of one of the valves E F G. The position ofthis arm Uis so arranged as that in the event of the cage beingsupported upon the floor of theli-ft-well, for instance, it will raisesaid spindle so as to open said valve, and thus allow the pressurewaterto flow into one of the governing-cylinders B, O, or D as soon as thestarting-valve t is operated in the ordinary way, it being of courseunderstood that as soon as the lift is started the piston h inthecylinder H comes into operation and regulates the supply of waterinto said governing-cylinders, as above described.

The operation depends simply upon the adjustment of the arm U, plunger hin the cylinder H, and the strength of the spring 71 When the cage restson the fioor of the well, there is no longer any pressure exerted in thecylinder H, and therefore the spring if can force the plunger it downinto said cylinder far enough to turn the shaft h sufficiently to causethe arm U on it to raise the valve, to whose spindle it is connected.The lift can then be startedin the ordinary way by operating thestarting -valve, and when once started the pressure in the mainrain-cylinder will cause the necessary valve to be opened, so as todirect the power-water into one or other of the operating-cylinders.

Instead of employing the variable pressure of water in the mainoperating-cylinder A of the hydraulic machine, I may, if preferred,connect the end of the haulage or lifting rope V to a lever h, fulcrumedupon a suitable support and connected at one end with an adjustablespring h and at the other end with a rock-shaft h, fitted with cams,such as are illustrated at e f 9 whereby the valves E F G may be openedor closed, according to the weight in the cage, in a similar manner towhen said rock-shaft h is operated by said variable pressure of water inthe main operating-cylinder. The operation of this modification of myinvention will be readily understood on reference to Fig. 15, it beingobvious that any increase or decrease of weight in the lift will pulldown the end of the rope V and will extend the spring h and so rock theshaft 71 a certain amount, thus bringing one or other of said cams orpawls 6 9 into operation.

Having now particularly described and as certained thenature of my saidinventionand in what manner the same is to be performed, I declare thatwhat I claim is 1'. The .combination, with the main operating-cylinderof a hydraulic machine, of a plurality of governing-cylinders, such as B0, whose pistons are of different areas, connected one with said maincylinder and-therest with valves, such as E FG, and means forautomatically opening andclosing the same according to the pressure insaid main operating-cylinder, substantially as and for the purposesherein described and explained, and as illustrated in my drawings. I

2. In a hydraulic machine, the combination, with the mainoperating-cylinder, of a plurality of governingcylinders having pistonsof different'areas, a corresponding number of valves connected with saidgoverning-cylinders, and means for automatically operating the saidvalves, substantially as set'forth,

3. The combination, with themain cylinder, a plurality ofgoverning-cylinders provided with pistons of different areas, one ofsaid cylinders being connected to said main cylinder and valvesconnected therewith, of

. a rock-shaft, pawls, or analogous devices fitted thereon, each adaptedto open one of said valves, and a piston or plunger connected to saidrock-shaft, substantially as and for the purpose set forth.

4. In apparatus for automatically regulating the amount of power-waterused in bydraulic machinery according to the weight to be raised or workdone, the combination, with the main cylinder and a plurality ofgoverning-cylinders fitted with pistons of different areas and connectedeach with a separate valve, one of said governing-cylinders beingconnected directly to the main cylinder, of a rock-shaft, such as h, andpawls or catches, such as e f g, fitted thereon and adapted to engagewith trip-levers, such as e f g connected with the spindles of saidvalves, said pawls, catches, or cams being arranged in differentrelative positions around said shaft, so as to operate upon the spindlesof and so open said valves in rotation, and means for returning saidshaft to its normalposition, substantially as and for the purposesherein described.

5. In an apparatus for automatically regu lating the amount ofpower-water used in hydraulic machinery according to the weight to beraised or work done, the combination, with the spindles, such as fg, ofa pair of valves, such as F G, an arm or lever,'such as P, mounted uponamok-shaft, such as h, carrying pawls, catches, or cams, whereby saidspindles .maybe raised to opensaid valves, together with avertically-slidin g. frame, such as p, engaging with saidspindles andfitted with a pair of pawls, such as p,wherewith said arm can engage,substantially as and for the purposes herein described and explained,and as illustrated in my drawings.

6. In apparatus for use in hydraulic machinery for automaticallyreturning a certain proportion of water to the water-supply, thecombination, with a plurality of cylinders containing pistons or rams ofvarying areas and connected to said water-supply by pipes fitted withback-pressure or retention valves, of a corresponding number of stopvalves, and means whereby one of said valves willbe automatically closedaccording to the pressure in the main operating-cylinder, substantiallyas set forth.

7. In an apparatus for regulating theamount of water used in hydraulicmachinery, the combination of a main operating-cylinder, apressureqnain, a cylinder communicating therewith and with the mainoperating-cylinder, a piston in said cylinder, a spring acting on saidpiston, a valve R, a spindle on said piston, a shaft connected thereto,and spring g on said spindle adapted to actuate said shaft, and valves EF G, substantially as and for the pn rposes specified.

S. In apparatus of the class herein described, the combination, with apower-main, of a main cylinder and a series of governingcylinders, oneof said cylinders connected to said main cylinder, and a series ofvalves serving to open communication between said power-main andgoverning-cylinders, and a piston controlled by water-pressure andconnected by suitable means to the said valves, substantially as setforth and described.

0. In an apparatus for automatically regulating the amount ofpower-water used in hydraulic machinery according to the weight. to beraised, the combination, with valves E F G, a rock-shaft, and devicesthereon for the purpose specified, of an arm 1), having pawls 19, saidarm engaging by means of a crosshead on spindles one or more of saidvalves, the arm P upon said rock-shaft adapted to engage said pawls uponsaid arm to open one or more of said valves, substantially as described.

GEORGE SMITH DUNCAN.

Vitnesses:

WALTER SMYTI-IE BAYSTON, EDWIN WILSON.

